Magnetism arising from Mexican-hat-like band dispersion in the WSe 2 /SnS 2 heterostructure via interlayer strain.

Mexican-hat-like band dispersion is extremely critical to the realization of hole-doping-induced magnetism in monolayer metal monochalcogenides. However, it is absent from transition-metal dichalcogenides (TMDCs),i.e., WSe2. Herein, using first-principles calculations, we show that Mexican-hat-like band dispersion can be achieved by applying interlayer strain (epsilon) in the WSe2/SnS(2)van der Waals (vdW) heterostructure when epsilon exceeds 15%. This is because in the strain-induced distorted trigonal prismatic crystal field, at the valence band edge, the W_d(z)(2)orbitals shift upward around the Gamma point, while the double-degenerate W_d(xy)/d(x)(2)-y(2)orbitals shift downward at theKpoint, resulting in Mexican-hat-like band dispersion near the Gamma point when the energy level of the Gamma point surpasses that of theKpoint. On account of the appearance of the Mexican-hat-like band edge (MHBE), hole-doping in the strained WSe2/SnS(2)heterostructure induces magnetization readily from the nonmagnetized phase. Our findings may provide a new strategy for the realization of magnetized TMDC-based vdW heterostructures.